Asphalt-impregnated linoleum-type articles and method of making same



AP111 6, 1955 G. w. STANTON ET AL 2,707,157

ASPHALTJ-IMPREGNATED LINOLEUM-TYPE ARTICLES AND METHOD OF MAKING SAMEFiled Jan. 14, 1952 e ,w o/eoresmous Myer WWW j 5 me 1N VENTORS GeorgeW////'am .S/an/on Thomas C. Spence ATTORNEYS United States Patent O2,707,157 ASPHALT-IMPREGNA'IED LINOLEUM-TYPE ARTI- 'CLES AND METHOD orMAKING SAME George William Stanton, Walnut Creek, and Thomas C.

" Spence, Concord, Calif., assignors to The Dow Chemical Company,Midland, Mich, a corporation of Delaware Application January 14, 1952,Serial No. 266,372 -13 Claims. (Cl. 117-76) coatedsheet is leveled withan oleoresinous coat, and l the latter, after being dried, is coatedwith a pigmented wear layer or color coat. The pigmented surfacecoatr-ing commonly, carries a .the asphalt employed is of western (e.g., California) origin, it has beenundesirableto use light colors orpas- -telwshades in the outer color coat because of the. strong tendencyfor fractions of the asphaltto bleed through .the. oleoresinous layer,causing objectionable and un- .sightly discoloration in the color coat.Such discoloratype, a feltor other absorbent distinctive color pattern.When Gil tion becomes apparent before the manuiacturingprocess,iscomplete, as the bleeding .is accelerated by the heat employecLtospeed the drying or. curingof the composite .article...Attempts havebeen made to seal the oleoreslnous level coating, to prevent asphaltbleeding, by means .of; casein, vegetable proteins or ,suchhydrophilic.colqgloids asmelhylcellulose or hydroxyethyl cellulose. These:haveprovenimpractical becausewthey are'all sensitive to Water and. evenif some of them show initial adherence to the oleoresinous-layer or theoverlying pigmented 1,coat,..they.fail in. storage or in service whenexposed to moisture. it has. also been proposed to. use vastyrene-.butadiene synthetic rubberlikercopolymer as a seal betweenthe color orwear layer and the oleoresinous layer, and, while this has shown somedegree ofsuccess with .,easternandimported asphalt-s, ithas beenunsuccessful .L.Wiih asphalts from the western states. I

it is the. principal object of .the present invention to provide asealing coat for use in linoleum-type articles .which willadhere to anoleoresinous coating .over western asphalt impregnated fibrous base andto an overlying pig- .mented. wearlayer, even in damp storage, and willprevent staining of? the colorcoating by the asphalt. "A. relatedobjectis to providea linoleunrtypearticle, based .ponlwesternasphaltimpregnated felt, or the like, in which the color coating may be.of white or pastel shades with- (outdanger that the asphalt will strikethrough and dis color. the outer coating.-, a

It has now been found that the prior difilculties can be avoided, and,-the foregoing objects can be realized, by. applying, oventheoleoresinous coat and under the .-color. or .wear coat, a continuouscoatingof a film forming composition, the solidsgportion of whichconsists chiefly of acopolymer in which vinylidene chloride is. acharacterizing copolymerizcd constituent. Such copoly- 'mers include thebinary and ternary copolymers of or moreaper cent byweight ofvinylidene. chloride, the balance being one or two othermonoethylenicallyunsaturated compounds such as vinyl chloride, vinylacetate, acrylonitrile, and the alkyl (1 ,to 8 carbon atoms) .acrylatesand ,methacrylates. All such copolymers are inert to the action ofdrying oils and other linoleum raw materials at the temperaturesemployed in making linoleum. .Thecopolymers may be applied as asolvent-cast coatingover the oleoresinous leveling layer, but it ispreferred to use the aqueous latex-like emulsion of those .trvinylidenechloride copolymers .whoselatices deposit a continuous, oil imperviousfilm. After the first copolymer coat is dried, a second such coat may beapplied,

if desired, to cover and seal any pinholes in the first ice coat. Overthe dried sealing coat or coats of copolymcr there is applied the wearlayer, which may also be a color coat. The wear layers most commonlyused are long oil paints or enamels or they may be clear or pi mentedvinyl resin organosols or plastisols. Whatever the nature of the wearlayer, the seal coat of vinylidene chloride copolymer protects it fromdiscoloration due to asphalt bleeding, and White or pastel shades can beused safelyin such surface coatings.

. When the seal coat of the present invention is a latexlike emulsion ofa'vinylidene chloride copolymer, it is preferred to modify the normallatex composition by dispersing therein a Water dispersible proteinsuchas casein or soya protein, or a hydrophilic cellulose ether .such asmethyl or hydroxyethyl cellulose, in amounts from 0.1 to 15 per cent ofthe weight of the dispersed polymer. These agents aid the cohesionbetween the deposited copolymer film and the underlying oleoresinouslayer. They are not necessary, and are omitted whenever the copolymerseal coat is deposited from organic solution rather than from aqueousemulsion.

It is not necessary that the seal coat. be thick, if it is continuousand substantially free from macropores. Thus, coatings as light as 1.5to 3 pounds of .copolymer over an area of 100 square yards are capableof effecting the desired result. It is preferable to apply twosuccessive thin coats of the copolymer rather than a single thickercoat, as the'possibility of pinholes in a double coat is materially lessthan in any single coat.

Thefollowing examples illustrate the practice of the invention. in allof the tests reported in the examples there was used a commercialasphalt-impregnated felt, made from Western asphalt, having a highlyfilled paint backing coat and a commercial and highly filledoleoresinous leveling coat. The latter had been applied as twosuccessive layers, thefirst 0.007..inch,thick and the second 0.016 inchthick, with intervening and subsequent curing treatment to dry the oilin the composition. In each case, the seal coat was applied to samples3.5. inches wide and 12 inches long, at the reported rate and theresulting assembly was dried. There was then applied a white pigmentedenamel color coat at a wet thickness of 0.012 inch, The color coat, whendried, was about 0.008 inch thick. The eifectiveness of the sealedat asan asphalt barrier was determinedby subjecting the article to atemperature of Chin a circulating air oven for 48 hours. This isa normaltreatment in the manufacture of linoleum products, or is the equivalentof a longer curing treatment at slightly lower temperatures. By the endof this curing period any defects in the product are readily observable,including any surface discoloration due to migration of asphaltfractions or any separation of the color coat from the seal coat. Theadhesion rating of the color coat is made after the heat treatment andafter flexing a sample of the product at room, temperature from 5 to 10times through an angle of about degrees with a bending radius of about 1inch. It is then attempted to peel the color coat from the article,first on the dry article, then on a water-soaked sample, then on aredried sample. The results are rated according to an arbitrarynumerical scale, perfect adhesion being rated as 1, and complete failureas 5. Ratings from 1 to 3 are considered satisfactory for commercialuse.

, The effectiveness of the seal coat as a barrier against asphaltstaining is rated by a similar numerical index in which an unstainedproduct is rated as l, a product with 1 to 2 small stains is rated 2,and a product with over 8 small stains, or with any massive stains, inthe 42 square inch area of the sample, is rated 5. Ratings of 1 or 2 areacceptable in a commercial product. The examples merely identify thesealing composition and the method in which it was applied, andcomparatve tests of the products are tabulated after the examples.

EXAMPLE 1 The seal coat was applied as two successive layers at a totalweight of about 3 pounds of polymer solids per square yards, the firstlayer being air dried before the second was applied. The coatingcomposition was an aqueous emulsion initially containing 53 per cent byweight of the ternary copolymer of 90 per cent vinylidene copolymeremulsions employed.

-This is possible with chloride, 3 per cent acrylonitrile and 7 per centethyl acrylate, the latex having been diluted with water to 26 per centsolids before use.

EXAMPLE 2 The coating procedure was that of Example 1, and the coatingcomposition was the same except that 0.1 per cent, based on the weightof copolymer solids, of hydroxyethyl cellulose was dissolved in theaqueous phase of the emulsion.

EXAMPLE 3 EXAMPLE 4 The procedure of Example 1 was used, and thecopolymer emulsion was modified by dispersion therein of one of thefollowing: (a) 5 per cent casein; (b) per cent casein; (c) 9 per centalpha-protein; (d) 5 per cent corn protein; (e) 5 per cent soya protein;(1) 5 per cent watersoluble urea-formaldehyde resin.

EXAMPLE 5 powdered copolymer made from 85 per chloride and per centacrylonitrile was dissolved to form a per cent solution in methyl ethylketone. This was applied at a coating weight (solids basis) of 1.5pounds per 100 square yards, and the solvent was evaporated beforeapplying the color coat.

Table A dried and cent vinylidene Adhesion As halt Sealing Examp pRating Rating It is observed that best water-dispersible protein orhydrophilic colloid is present results are obtained when a awater-dispersible resin or in the aqueous phase of the Such agents arenot helpful when copolymer lacquers are used to deposit the seal coat.

Numerous other tests have shown the general utility for the presentpurpose of copolymers of vinylidene chloride which, by virtue of theirhigh vinylidene chloride content (at least 70 per cent) are imperviousto the usual staining fractions of asphalt, especially of westernasphalt. If applied from aqueous emulsion, the emulsion should be onecapable of depositing a continuous film.

many vinylidene chloride copolymers in their unmodified condition, andwith the others when 10 to 20 per cent plasticizer is dispersed in theemulsion, as is well-known. Thus, plasticized emulsions of a copolymerof 85 per cent vinylidene chloride and 15 per cent vinyl chloride, or anunplasticized emulsion of a copolymer of 85 per cent vinylidene chlorideand 15 per cent ethyl acrylate may be used with about equivalent sealingeffect. Unplasticized copolymers of 70 to 77 per cent vinylidenechloride and 30 to 23 per cent' vinyl chloride, when made in emulsion,form continuous films which may be used in the process of the invention.

The invention finds its greatest utility in those linoleum articleswhich have white or light colors in their wear layer, but is useful alsoin avoiding changes in color of darker pigmented coatings. While a sealcoat which will prevent bleeding of other asphalts may not do so withwestern asphalt, the seal coats of this invention will prevent stainingby any asphalt used in linoleum manufacture. Since the color coat orwear layer in most linoleum is either an enamel or paint with avegetable oil vehicle or is a synthetic resin or polymer plastisol,

and since all such coats are capable of absorbing and dispersing thediscoloring fractions of asphalt, the precise nature of the wear layeris not critical to the invention. Similarly, since the various dryingoil compositions used in leveling and bodying a linoleum structure areall penetrable by the discoloring constituents of asphalts, the identityof such oleoresinous layer is not critical to the invention.

The new article of the present invention is illustrated in cross-sectionin the single figure of the accompanying drawing.

We claim:

1. In a linoleum type article comprising an asphalt impregnated fibroussheet and having thereover a wear layer which is compatible withdiscoloring fractions of asphalt and comprises a material from the classconsisting of oil base paints and enamels and synthetic resin andpolymer plastisols, the improvement which consists in interposingbetween the asphalt impregnated sheet and the wear layer a sealing coatconsisting essentially of a continuous deposit of a copolymer of atleast 70 per cent vinylidene chloride, the balance of the copolymerbeing composed of 1 to 2 compounds from the group consisting of vinylchloride, vinyl acetate, acrylonitrile, and the alkyl esters of acrylicand methacrylic acid containing from 1 to 8 carbon atoms in the alkylgroup.

2. The article claimed in claim 1, wherein the said sealing coat isinterposed between the wear layer and an oleoresinous leveling coatwhich is immediately over the asphalt impregnated fibrous sheet.

3. The article claimed in claim 1, wherein the asphalt is a westernasphalt.

4. The article claimed in claim I, wherein the wear layer contains lightcolors, easily discolored by asphalt constituents. I

5. The article claimed in claim 1, wherein the sealing coat consistsessentially of a copolymer of about per cent vinylidene chloride, about3 per cent acrylonitrile and the balance ethyl acrylate.

6. The article claimed in claim 1, wherein the sealing coat consistsessentially of a copolymer of about 85 per cent vinylidene chloride andcomplementarily about 15 per cent acrylonitrile.

7. The article claimed in claim 1, wherein the sealing coat contains, inaddition to the copolymer, from 0.1 to 15 per cent of awater-dispersible protein adhesive.

8. The article claimed in claim 1, wherein the sealing coat contains, inaddition to the copolymer, about 10 per cent of casein.

9. The article claimed in claim 1, wherein the sealing coat contains, inaddition to the copolymer, about 5 per cent of a water-solubleurea-formaldehyde resin.

10. The article claimed in claim 1, wherein the copolymeric sealing coatrepresents about 1.5 to' 3 pounds of copolymer per square yards of thearticle.

11. In a method of making a linoleum type article, the improvement whichconsists in depositing over an oleoresinous level coated asphaltimpregnated fibrous base a continuous coating of a copolymer containingat least 70 per cent vinylidene chloride, the balance of the copolymerbeing composed of 1 to 2 compounds from the group consisting of vinylchloride, vinyl acetate, acrylonitrile, and the alkyl esters of acrylicand methacrylic acid containing 1 to 8 carbon atoms in the alkyl group,drying said coating, and applying the wear layer over the copolymercoat, said wear layer being one which is compatible with discoloringfractions of asphalt and comprises a material from the class consistingof oil base paints and enamels and synthetic resin and polymerplastisols.

12. The method claimed in claim 11, wherein the copolymer coat isdeposited from a film-forming emulsion of the copolymer.

13. The method claimed in claim 11, wherein the copolymer coat isapplied at a rate to leave from 1.5 to 3 pounds of copolymer per 100square yards of the article.

References Cited in the file of this patent UNITED STATES PATENTS2,529,799 Crockett Nov. 14, 1950 2,624,682 Hazeltine 5. Jan. 6, 1953FOREIGN PATENTS 552,500 Great Britain 1943

1. IN A LINOLEUM TYPE ARTICLE COMPRISING AN ASPHALT IMPREGNATED FIBROUSSHEET AND HAVING THEREOVER A WEAR LAYER WHICH IS COMPATIBLE WITHDISCOLORING FRACTIONS OF ASPHALT AND COMPRISES A MATERIAL FROM THE CLASSCONSISTING OF OIL BASE PAINTS AND ENAMELS AND SYNTHETIC RESIN ANDPOLYMER PLASTISOLS, THE IMPROVEMENT WHICH CONSISTS IN INTERPOSINGBETWEEN THE ASPHALT IMPREGNATED SHEET AND THE WEAR LAYER A SEALING COATCONSISTING ESSENTIALLY OF A CONTINUOUS DEPOSIT OF A COPOLYMER OF ATLEAST 70 PER CENT VINYLIDENE CHLORIDE, THE BALANCE OF THE COPOLYMERBEING COMPOSED OF 1 TO 2 COMPOUNDS FROM THE GROUP CONSISTING OF VINYLCHLORIDE, VINYL ACETATE, ACRYLONITRILE, AND THE ALKYL ESTERS OF ACRYLICAND METHACRYLIC ACID CONTAINING FROM 1 TO 8 CARBON ATOMS IN THE ALKYLGROUP.